Abstract. Radar observations can be used to obtain accurate orbital elements for near-Earth objects (NEOs) as a result of the very accurate range and range-rate measureables. These observations allow predicting NEO orbits further into the future, and also provide more information about the properties of the NEO population. This study evaluates the observability of NEOs with the EISCAT 3D high-power large-aperture radar, which is currently under construction. Three different populations are considered: NEOs passing by the Earth with a size distribution extrapolated from fireball statistics, catalogued NEOs detected with ground-based optical telescopes, and temporarily-captured NEOs, i.e., minimoons. Two types of observation schemes are evaluated: serendipitous discovery of unknown NEOs passing the radar beam, and post-discovery tracking of NEOs using a priori orbital elements. The results indicate that 60–1200 objects per year with diameters D > 0.01 m can be discovered. Assuming the current NEO discovery rate, approximately 20 objects per year can be tracked post-discovery near closest approach. Only a marginally smaller number of tracking opportunities are also possible for the existing EISCAT UHF system. The minimoon study, which used a theoretical population model, orbital propagation, and a model for radar scanning, indicates that approximately 7 objects per year can be discovered using 8–16 % of the total radar time. If all minimoons had known orbits, approximately 80–160 objects per year could be tracked using a priori orbital elements. The results of this study indicate that it is feasible to perform routine NEO post-discovery tracking observations using both the existing EISCAT UHF radar and the upcoming EISCAT 3D radar. Most detectable objects are within 1 LD distance of the radar. Such observations would complement the capabilities of the more powerful planetary radars that typically observe objects further away from Earth. It is also plausible that EISCAT 3D could be used as a novel type of an instrument for NEO discovery, assuming a sufficiently large amount of radar time can be used. This could be achieved, e.g., by time-sharing with ionospheric and space debris observing modes.

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We have applied three different methods to examine the observability, both tracking and discovery, of near-Earth objects (NEOs) by the EISCAT 3D radar system currently under construction. There are to to our knowledge no previous studies done on the expected discovery-rates of NEOs using radar systems. We show that it is feasible to regularly track NEOs and minimoons. We also show it is possible to discover new NEOs and minimoons with EISCAT 3D, something never before done with radar systems.

We have applied three different methods to examine the observability, both tracking and...